1. Field of the Invention
The invention relates to a procedure for operating a pyrolysis plant in which waste material, especially waste material containing hydrocarbons such as rubber and/or plastic waste, is thermally decomposed and the hot pyrolysis gas produced is cooled in at least one preliminary cooling stage and at least one final cooling stage and at least a part of the cooled pyrolysis gas is stored in a gas reservoir.
2. Description of the Prior Art
In prior art pyrolysis plants of this type, the hot and combustible pyrolysis gas coming from the pyrolysis reactor with a temperature of approximately 400.degree. to 1,000.degree. C. and preferably 500.degree. to 700.degree. C., flows into the preliminary cooling stage in which it is cooled to a preliminary cooling temperature of approximately 120.degree. to 300.degree. C. and preferably 140.degree. to 200.degree. C. Subsequently, the pyrolysis gas is further cooled in at least one final cooling stage. This combustible, cooled pyrolysis gas is primarily used to meet an internal requirement, especially for heating the pyrolysis reactor and/or to provide fluidizing gas if the pyrolysis reactor is required to operate with a fluidized bed or a fluidized layer. The remaining pyrolysis gas is fed to a gas reservoir and is available for other applications, such as room heating.
For cost reasons, the final cooling stage and the other components connected downstream of the final cooling stage, such as, for example, a compressor and a gas reservoir, are only dimensioned and are only suitable for operating with a low temperature as compared with the operation of the preliminary cooling stage. It is therefore necessary to avoid penetration of hot pyrolysis gas into the final cooling stage and the components connected downstream in the event of an operational malfunction of the preliminary cooling stage, for example in the event of a failure of the coolant supply. This could be achieved by taking the plant out of operation in the event of an operational malfunction of the preliminary cooling stage. However, such a procedure would be very disadvantageous since the shut down and the start up of a pyrolysis plant require a certain time which is approximately two to five hours. Since the operational malfunctions of the preliminary cooling stage can in many cases be eliminated in a short time, the above-mentioned shut down of the pyrolysis plant is very uneconomical.